CN220934090U

CN220934090U - Solar cell and photovoltaic module

Info

Publication number: CN220934090U
Application number: CN202322518871.XU
Authority: CN
Inventors: 张远方; 郑霈霆; 杨洁; 张昕宇
Original assignee: Zhejiang Jinko Solar Co Ltd; Jinko Solar Co Ltd
Current assignee: Zhejiang Jinko Solar Co Ltd; Jinko Solar Co Ltd
Priority date: 2023-09-15
Filing date: 2023-09-15
Publication date: 2024-05-10
Anticipated expiration: 2033-09-15

Abstract

The embodiment of the utility model relates to the field of photovoltaics, and provides a solar cell and a photovoltaic module, wherein the solar cell comprises: a substrate having a first surface and a second surface, the substrate having electrode regions and non-electrode regions alternately arranged; the first surface of the electrode region is provided with a first surface structure, the first surface of the non-electrode region is provided with a second surface structure, and the roughness of the first surface structure is smaller than that of the second surface structure; the tunneling dielectric layer covers the first surface structure; the first doped conductive layer is positioned on one side of the tunneling dielectric layer away from the substrate; an intrinsic passivation layer on the second surface of the substrate; the second doped conductive layer is positioned on one side of the intrinsic passivation layer away from the substrate; the first doped conductive layer and the second doped conductive layer have different conductive types; and the transparent conductive layer covers the surface of the second doped conductive layer.

Description

Solar cell and photovoltaic module

Technical Field

The embodiment of the utility model relates to the field of photovoltaics, in particular to a solar cell and a photovoltaic module.

Background

Currently, with the gradual depletion of fossil energy, solar cells are increasingly used as new energy alternatives. A solar cell is a device that converts solar light energy into electrical energy. The solar cell generates carriers by utilizing the photovoltaic principle, and then the carriers are led out by using the electrodes, so that the electric energy can be effectively utilized.

Current solar cells mainly include IBC cells (crossed back electrode contact cells, INTERDIGITATED BACK CONTACT), TOPCON (Tunnel Oxide Passivated Contact, tunnel oxide passivation contact) cells, PERC cells (passivation emitter and back cells, PASSIVATED EMITTER AND REAL CELL), heterojunction cells, and the like. The photoelectric conversion efficiency of the solar cell is improved by reducing optical loss and reducing photo-generated carrier recombination on the surface and in the body of the silicon substrate through different film layer arrangement and functional limitation.

Disclosure of utility model

The embodiment of the utility model provides a solar cell and a photovoltaic module, which are at least beneficial to improving the photoelectric conversion efficiency of the solar cell.

According to some embodiments of the present utility model, an aspect of an embodiment of the present utility model provides a solar cell, including: a substrate having a first surface and a second surface, the substrate having alternately arranged electrode regions and non-electrode regions; the first surface of the electrode region is provided with a first surface structure, the first surface of the non-electrode region is provided with a second surface structure, and the roughness of the first surface structure is smaller than that of the second surface structure; a tunneling dielectric layer covering the first surface structure; the first doped conductive layer is positioned on one side of the tunneling dielectric layer away from the substrate; an intrinsic passivation layer on the second surface of the substrate; a second doped conductive layer located on a side of the intrinsic passivation layer remote from the substrate; the first doped conductive layer has a first doping element, the second doped conductive layer has a second doping element, and the conductivity type of the first doping element is different from the conductivity type of the second doping element; and the transparent conductive layer covers the surface of the second doped conductive layer.

In some embodiments, the second surface structure comprises a plurality of first raised structures; the first doped conductive layer is provided with a third surface structure on one side far away from the tunneling dielectric layer, the third surface structure comprises a plurality of microprotrusion structures, and the size of each microprotrusion structure is smaller than that of the first protruding structure.

In some embodiments, the microprotrusion structure is less than 1um in size.

In some embodiments, the shape of the microprotrusion structure includes a pyramid shape, a sinusoidal shape, or a parabolic shape.

In some embodiments, the first surface structure comprises a planar face.

In some embodiments, the tunneling dielectric layer and the first doped conductive layer are conformal with the first surface structure.

In some embodiments, the substrate has a third doping element therein, the first doping element having a conductivity type that is the same as a conductivity type of the third doping element or the second doping element having a conductivity type that is the same as a conductivity type of the third doping element.

In some embodiments, further comprising: and the emitter is positioned on the first surface of the substrate, the tunneling dielectric layer is positioned on the emitter surface of the electrode area, and the emitter is conformal with the first surface structure and the second surface structure.

In some embodiments, the second surface has a textured structure, the intrinsic passivation layer, the second doped conductive layer, and the transparent conductive layer being conformal to the textured structure.

In some embodiments, further comprising: a first electrode located in the electrode region, the first electrode in electrical contact with the first doped conductive layer; and the second electrode is positioned in the electrode area and is electrically contacted with the transparent conductive layer.

According to some embodiments of the present utility model, another aspect of the embodiments of the present utility model further provides a photovoltaic module, including: a cell string formed by connecting a plurality of solar cells according to any one of the above embodiments; the packaging adhesive film is used for covering the surface of the battery string; and the cover plate is used for covering the surface of the packaging adhesive film, which is away from the battery strings.

The technical scheme provided by the embodiment of the utility model has at least the following advantages:

In the solar cell provided by the embodiment of the utility model, the roughness of the first surface structure is smaller than that of the second surface structure, so that the high roughness of the substrate surface of the non-electrode area represents that the substrate surface of the non-electrode area has a concave-convex structure, and the concave-convex structure can increase the internal reflection of incident light rays, so that the light ray utilization rate is improved; the low roughness of the substrate surface of the electrode region represents that the substrate surface of the electrode region is smoother, so that the deposition performance of the tunneling dielectric layer and the film layer of the first doped conductive layer deposited on the substrate surface of the electrode region is better, the density is higher, and the surface defect of the substrate surface of the electrode region can be reduced by playing a better passivation effect. The front surface is a local TOPCon battery structure, and the back surface is a heterojunction structure, so that the passivation effect of the battery is improved, and the battery efficiency is improved.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, which are not to be construed as limiting the embodiments unless specifically indicated otherwise; in order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the conventional technology, the drawings required for the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

Fig. 1 is a top view of a solar cell according to an embodiment of the present utility model;

FIG. 2 is a schematic view of a first cross-sectional structure of FIG. 1 along the line A1-A2;

FIG. 3 is a schematic view of a first cross-sectional structure of the cross-section B1-B2 of FIG. 1;

FIG. 4 is a schematic view of a second cross-sectional structure of FIG. 1 along the line A1-A2;

FIG. 5 is a schematic view of a second cross-sectional structure of FIG. 1 along the line B1-B2;

FIG. 6 is a schematic view of a third cross-sectional structure of FIG. 1 along the line A1-A2;

FIG. 7 is a schematic view of a third cross-sectional structure of FIG. 1 along the line B1-B2;

FIG. 8 is a schematic view of a fourth cross-sectional structure of FIG. 1 along the line A1-A2;

fig. 9 is a schematic structural diagram of a photovoltaic module according to an embodiment of the present utility model.

Detailed Description

As known from the background art, the photoelectric conversion efficiency of the current solar cell is poor.

The embodiment of the utility model provides a solar cell, wherein the roughness of a first surface structure is smaller than that of a second surface structure, so that the roughness of the substrate surface of a non-electrode area is high, which means that the substrate surface of the non-electrode area is provided with a concave-convex structure, and the concave-convex structure can increase the internal reflection of incident light rays, thereby improving the utilization rate of the light rays; the low roughness of the substrate surface of the electrode region represents that the substrate surface of the electrode region is smoother, so that the deposition performance of the tunneling dielectric layer and the film layer of the first doped conductive layer deposited on the substrate surface of the electrode region is better, the density is higher, and the surface defect of the substrate surface of the electrode region can be reduced by playing a better passivation effect. The front surface is a local TOPCon battery structure, and the back surface is a heterojunction structure, so that the passivation effect of the battery is improved, and the battery efficiency is improved.

Embodiments of the present utility model will be described in detail below with reference to the attached drawings. However, it will be understood by those of ordinary skill in the art that in various embodiments of the present utility model, numerous specific details are set forth in order to provide a thorough understanding of the present utility model. The claimed utility model may be practiced without these specific details and with various changes and modifications based on the following embodiments.

Fig. 1 is a top view of a solar cell according to an embodiment of the present utility model; FIG. 2 is a schematic view of a first cross-sectional structure of FIG. 1 along the line A1-A2; fig. 3 is a schematic view of a first cross-sectional structure of the cross-section B1-B2 of fig. 1.

Referring to fig. 1 to 3, according to some embodiments of the present utility model, an aspect of an embodiment of the present utility model provides a solar cell, including: the substrate 100, the substrate 100 has a first surface 21 and a second surface 22, and the substrate 100 has electrode regions 10 and non-electrode regions 11 alternately arranged.

In some embodiments, the material of the substrate 100 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, which may be silicon or silicon, for example. The elemental semiconductor material may be in a single crystal state, a polycrystalline state, an amorphous state, or a microcrystalline state (a state having both a single crystal state and an amorphous state, referred to as a microcrystalline state), and for example, silicon may be at least one of single crystal silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

In some embodiments, the material of the substrate 100 may also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanium, silicon carbide, gallium arsenide, indium gallium, perovskite, cadmium telluride, copper indium selenium, and the like. The substrate 100 may also be a sapphire substrate, a silicon-on-insulator substrate, or a germanium-on-insulator substrate.

In some embodiments, the substrate 100 may be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type doping element, which may be any of v group elements such As phosphorus (P) element, bismuth (Bi) element, antimony (Sb) element, and arsenic (As) element. The P-type semiconductor substrate is doped with a P-type element, and the P-type doped element may be any one of group iii elements such as boron (B) element, aluminum (Al) element, gallium (Ga) element, and gallium (In) element.

Referring to fig. 2, the first surface 21 of the substrate 100 may be a front surface and the second surface 22 may be a back surface, or the first surface 21 of the substrate 100 may be a back surface and the second surface 22 may be a front surface, i.e., the solar cell is a single-sided cell, the front surface may be a light receiving surface for receiving incident light, and the back surface may be a back surface. In some embodiments, the solar cell is a double sided cell, that is, the first surface 21 and the second surface 22 of the substrate 100 can be used as light receiving surfaces, and can be used for receiving incident light.

In some embodiments, the electrode region 10 refers to a region facing the first electrode 109 or the second electrode 108 within the substrate 100 in the thickness direction of the substrate 100, or may be understood as a region where the first electrode 109 or the second electrode 108 is orthographic projected on the substrate 100. Conversely, the non-opposing region of the first electrode 109 or the second electrode 108 in the substrate 100 is the non-electrode region 11. The area of the electrode region 10 is greater than or equal to the orthographic projection of the first electrode 109 or the second electrode 108 on the substrate 100, so that the contact area of the first electrode 109 or the second electrode 108 is ensured to be the electrode region 10.

It should be noted that the above definition of the electrode region 10 and the non-electrode region 11 is directed to a non-IBC cell, i.e. two conductive electrodes with different polarities of the solar cell are respectively located on opposite sides of the substrate 100, rather than on the same side of the substrate 100. When the solar cell is an IBC cell or two conductive electrodes of different polarities are located on the same side of the substrate 100, the electrode region 10 refers to a region where conductive electrodes of one polarity are facing and a region where conductive electrodes of the other polarity are facing, and the non-electrode region 11 refers to a region where conductive electrodes of both polarities are not facing.

In some embodiments, a solar cell includes: the first surface 21 of the electrode region 10 has a first surface structure 31, the first surface 21 of the non-electrode region 11 has a second surface structure 32, and the roughness of the first surface structure 31 is smaller than that of the second surface structure 32, so that the roughness of the substrate surface of the non-electrode region is high to represent that the substrate surface of the non-electrode region has a concave-convex structure, and the concave-convex structure can increase the internal reflection of incident light, thereby improving the utilization rate of the light; the low roughness of the substrate surface of the electrode region represents that the substrate surface of the electrode region is smoother, so that the deposition performance of the tunneling dielectric layer and the film layer of the first doped conductive layer deposited on the substrate surface of the electrode region is better, the density is higher, and the surface defect of the substrate surface of the electrode region can be reduced by playing a better passivation effect.

It should be noted that the difference in roughness is due to the fact that the height of the texture of the surface of the substrate 100 of the non-electrode region 11 is greater than the height of the texture of the surface of the substrate 100 of the electrode region 10 or the degree of concavity and convexity of the surface of the substrate 100 of the non-electrode region 11 is greater than the degree of concavity and convexity of the surface of the substrate 100 of the electrode region 10. Roughness refers to the arithmetic average of the absolute value of the amount of Z-direction deviation from the average line over one sampling length. Roughness can be measured by comparison, photocutting, interferometry, and needle punching.

In some embodiments, the first surface structure comprises a planar surface comprising a polished surface.

The polished surface is a flat surface formed by removing the suede structure of the surface through polishing solution or laser etching. The surface flatness of the substrate 100 after polishing is increased, the reflection of long wave light is increased, and the secondary absorption of projection light is promoted, so that the short-circuit current is improved, meanwhile, the surface recombination of the substrate 100 is reduced due to the reduction of the specific surface area of the substrate 100, and the surface passivation effect of the substrate 100 can be improved.

It is understood that a planar surface refers to a relatively planar surface, rather than an absolutely planar surface, and a surface having a roughness of less than or equal to 5um and greater than or equal to-5 um is generally characterized as a planar surface. Further, it may also refer to a surface having a smaller roughness than the roughness of the first surface structure, the roughness of the second surface structure, and the roughness of the third surface structure.

In some embodiments, the second surface structure 32 comprises a regular-shaped pyramid-shaped pile structure and an irregularly-shaped black silicon. The inclined surface of the second surface structure 32 may increase internal reflection of the incident light, thereby improving absorption and utilization of the incident light by the substrate 100, and further improving cell efficiency of the solar cell.

Referring to fig. 2, the second surface structure 32 includes a plurality of first protrusion structures, and the arrangement height and size of at least one first protrusion structure 111 may be any range known to those skilled in the art, and the embodiment of the present utility model is not limited thereto.

Wherein the definition of the dimensions of the raised structures refers to: a region is arbitrarily designated within the range of the surface of the substrate 100, and the one-dimensional dimensions of the bottom surfaces of the respective first bump structures 111 in this region are detected and finally averaged. It will be appreciated that the dimensions of the raised structures refer to a range of average values for one region, not all ranges of dimensions for all first raised structures 111 within the substrate 100, and that all ranges of dimensions for the first raised structures are generally greater than the range of average values. For illustration, each of the first bump structures 111 in fig. 2 has the same morphology and a size equal to the average one-dimensional size.

It should be noted that the one-dimensional dimension refers to a distance between two opposite corners in the bottom surface pattern of the first bump structure. In some embodiments, the one-dimensional dimension may also be the distance between the two sides of the bottom surface pattern. Wherein the surfaces of the plurality of first bump structures remote from the first surface 21 are fitted so that a virtual surface can be constructed as a bottom surface, i.e., the bottom surface is a surface that appears in a simulation, and is not present in an actual battery. For example, a portion of the surface of the first protrusion structure remote from the first surface is flush with the bottom surface, and a portion of the surface of the first protrusion structure remote from the first surface is higher than the bottom surface or lower than the bottom surface is a second surface structure 32 included in an embodiment of the present application.

In some embodiments, the first bump structure 111 has a size between 100nm and 10um. The first bump structure 111 has a size of 100nm to 300nm, 300nm to 600nm, 600nm to 1000nm, 1um to 2um, 2um to 4um, 4um to 7um, or 7um to 10um. The height of the first bump structure 111 is 100nm to 10um. The height of the first bump structure 111 is 100nm to 450nm, 450nm to 700nm, 700nm to 1700nm, 1.7um to 3.2um, 3.2um to 6.1um, 6.1um to 8.5um, or 8.5um to 10um. The size of the first bump structure 111 may be within the above range to ensure that the defect of the first surface 21 of the substrate 100 is small, and the inclined surface of the first bump structure 111 may reflect the incident light multiple times, thereby improving the light utilization rate. In addition, the height of the first bump structure 111 refers to the vertical distance between the highest point of the first bump structure 111 away from the second surface 22 and the bottom surface.

In some embodiments, a solar cell includes: a tunneling dielectric layer 121, the tunneling dielectric layer 121 covering the first surface structure 31; the first doped conductive layer 122, the first doped conductive layer 122 is located on a side of the tunneling dielectric layer 121 away from the substrate 100.

In some embodiments, the tunneling dielectric layer 121 and the first doped conductive layer 122 form a passivation contact structure, the first doped conductive layer 122 can form an energy band bend on the surface of the substrate 100, and the tunneling dielectric layer 121 causes an asymmetric shift of the energy band on the surface of the substrate 100, so that a barrier to multiple carriers (also called majority carriers) in carriers is lower than a barrier to fewer carriers (also called minority carriers) in carriers, and therefore, multiple carriers can more easily perform quantum tunneling through the tunneling dielectric layer 121, while fewer carriers can hardly pass through the tunneling dielectric layer 121, so as to realize selective transmission of carriers.

In addition, tunneling dielectric layer 121 serves as a chemical passivation. Specifically, since the interface between the substrate 100 and the tunneling dielectric layer 121 has an interface state defect, the density of the interface state on the back surface of the substrate 100 is relatively high, and the increase of the density of the interface state promotes the recombination of photo-generated carriers, and increases the filling factor, the short-circuit current and the open-circuit voltage of the solar cell, so as to improve the photoelectric conversion efficiency of the solar cell. The tunneling dielectric layer 121 is disposed on the first surface 21 of the substrate 100, so that the tunneling dielectric layer 121 has a chemical passivation effect on the surface of the substrate 100, specifically: by saturating dangling bonds of the substrate 100, the defect state density of the substrate 100 is reduced, and the recombination center of the substrate 100 is reduced to reduce the carrier recombination rate.

In some embodiments, the material of tunnel dielectric layer 121 may include at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride.

The first doped conductive layer 122 acts as a field passivation effect. Specifically, an electrostatic field pointing to the inside of the substrate 100 is formed on the surface of the substrate 100, so that minority carriers escape from the interface, thereby reducing minority carrier concentration, reducing carrier recombination rate at the interface of the substrate 100, increasing open-circuit voltage, short-circuit current and filling factor of the solar cell, and improving photoelectric conversion efficiency of the solar cell.

The material of the first doped conductive layer 122 may include at least one of amorphous silicon, polysilicon, or silicon carbide. The first doped conductive layer 122 may be doped with the same type of doping element as the substrate 100, for example, the type of doping element of the substrate 100 is P-type, and the type of doping element in the first doped conductive layer 122 may also be P-type; the doping element type of the substrate 100 is N-type, and the doping element type in the first doped conductive layer 122 may also be N-type.

The concentration of the doping element in the first doped conductive layer 122 is greater than the concentration of the doping element in the substrate 100 to form a sufficiently high barrier on the back surface of the substrate 100 to enable the electrons in the substrate 100 to pass through the tunneling dielectric layer 121 into the first doped conductive layer 122.

In some embodiments, the thickness of the tunneling dielectric layer 121 is 0.5nm to 5nm, alternatively, the thickness of the tunneling dielectric layer 121 ranges from 0.5nm to 1.3nm, from 1.3nm to 2.6nm, from 2.6nm to 4.1nm, or from 4.1nm to 5nm. In any range, the thickness of the tunneling dielectric layer 121 is thinner, so that the quantum tunneling can be easily performed by the tunneling dielectric layer 121, and the selective transmission of carriers can be realized by the tunneling dielectric layer 121 with few electrons.

Referring to fig. 2, in some embodiments, the tunneling dielectric layer and the first doped conductive layer are conformal with the first surface structure. Therefore, the tunneling dielectric layer and the first doped conductive layer can conform to the shape of the first surface structure, so that the passivation effect is good, the surface defect of the first surface of the substrate is reduced, and the deposition effect of the tunneling dielectric layer and the first doped conductive layer is good.

In some embodiments, referring to fig. 4 and 5, fig. 4 is a schematic diagram of a second cross-sectional structure of fig. 1 along A1-A2; fig. 5 is a schematic view of a second cross-sectional structure of fig. 1 along the section B1-B2. The side of the first doped conductive layer 122 away from the tunneling dielectric layer 121 has a third surface structure 33, and the third surface structure 33 includes a plurality of micro-protrusion structures 112, and the size of the micro-protrusion structures 112 is smaller than that of the first protrusion structures 111.

In some embodiments, the third surface structure 33 comprises a regular-shaped pyramid-shaped pile structure and an irregularly-shaped black silicon. The inclined surface of the third surface structure 33 may increase internal reflection of the incident light, thereby improving absorption and utilization rate of the incident light by the substrate 100, and further improving cell efficiency of the solar cell.

In some embodiments, the roughness of the third surface structure 33 is greater than the roughness of the first surface structure 31, so that the flatness of the first surface structure 31 is better, the surface area of the substrate 100 is smaller, and thus the surface defects are fewer; the roughness of the third surface structure 33 is large, so that the contact performance between the first electrode 109 and the first doped conductive layer 122 is better, and a higher welding tension is provided between the first electrode 109 and the first doped conductive layer 122, so that the yield of the solar cell is improved.

In some embodiments, the shape of the microprotrusion structure 112 includes a pyramid shape, a sinusoidal shape, or a parabolic shape.

It should be noted that the dimensions of the micro-protrusion structure 112 are defined in the same manner as those of the first protrusion structure 111, and will not be described herein.

In some embodiments, the microprotrusion structure 112 is less than 1um in size. The microprotrusion structure 112 has a size less than 890nm. The microprotrusion structure 112 has a dimension less than 760nm. The microprotrusion structure 112 has a dimension less than 620nm. The microprotrusion structure 112 has a dimension less than 500nm. The microprotrusion structure 112 has a dimension less than 320nm. In this way, the dimension of the microprotrusion structure 112 is within the above-mentioned arbitrary range, and the dimension of the microprotrusion structure 112 is smaller, so that the etching time and the etching degree of the first doped conductive layer 122 are smaller, and more etching loss to the first doped conductive layer 122 is avoided, so as to ensure that the first doped conductive layer 122 has a good passivation effect.

In some embodiments, the height of the microprotrusion structure 112 is less than 1um. The height of the microprotrusion structure 112 is less than 910nm. The height of the microprotrusion structure 112 is less than 810nm. The height of the microprotrusion structure 112 is less than 590nm. The height of the microprotrusion structure 112 is less than 430nm. The height of the microprotrusion structure 112 is less than 220nm. Thus, the height of the micro-protrusion structure 112 is within any range, and the height of the micro-protrusion structure 112 is smaller, so that the roughness of the third surface structure 33 is smaller, and the passivation layer 104 is not only located at the concave position of the micro-protrusion structure 112, but also located at the convex position of the micro-protrusion structure 112, thereby better providing the interface recombination effect. Wherein, the height of the micro-protrusion structure 112 refers to the vertical distance between the highest point of the micro-protrusion structure 112 away from the first surface 21 and the bottom surface.

In addition, the height and the size of the micro-protrusion structure 112 are within the above ranges, so that the micro-protrusion structure 112 has a larger aspect ratio, and the inclined surface of the micro-protrusion structure 112 can reflect the incident light multiple times, thereby improving the light utilization rate.

In some embodiments, with continued reference to fig. 2, the solar cell includes: an intrinsic passivation layer 105, the intrinsic passivation layer 105 being located on the second surface 22 of the substrate 100; a second doped conductive layer 106, the second doped conductive layer 106 being located on a side of the intrinsic passivation layer 105 remote from the substrate 100; the first doped conductive layer 122 has a first doping element, the second doped conductive layer 106 has a second doping element, and the conductivity type of the first doping element is different from the conductivity type of the second doping element; and a transparent conductive layer 107, wherein the transparent conductive layer 107 covers the surface of the second doped conductive layer 106.

It will be appreciated that the transparent conductive layer 107 is electrically conductive and that carriers may pass through the intrinsic passivation layer, the second doped conductive layer and the transparent conductive layer in that order and eventually be collected by the second electrode.

In some embodiments, the interface between the intrinsic passivation layer 105 and the substrate 100 may form a higher open circuit voltage on the one hand, and may achieve a better passivation effect on the other hand, so that the conversion efficiency may be more easily improved.

In some embodiments, the material of the intrinsic passivation layer 105 includes intrinsic amorphous silicon, silicon oxide, silicon nitride, or silicon carbide. The thickness of the intrinsic passivation layer 105 may optionally be in the range of 2 microns or more and 10 microns or less, with 5 microns being preferred.

In some embodiments, the second doped conductive layer 106 comprises a composite thin film layer of one or more of N-doped or P-doped amorphous silicon, amorphous silicon oxide, amorphous silicon carbide, microcrystalline silicon, hydrogenated microcrystalline silicon, microcrystalline silicon oxide, microcrystalline silicon carbide, or polycrystalline silicon semiconductor thin films; the thickness of the second doped conductive layer 106 ranges from 4 to 30nm.

The hydrogenated microcrystalline silicon has a larger band gap and a narrower absorption spectrum range, so that the photoelectric conversion efficiency of the battery can be effectively improved, the series resistance is reduced along with the improvement of the crystallization rate, the filling factor is improved, and the effects of improving the output current of the battery and effectively prolonging the service life of the battery can be achieved.

In some embodiments, the transparent conductive layer 107 may include at least one of tin doped indium oxide (ITO), aluminum doped zinc oxide (AZO), cerium doped indium oxide, and tungsten doped indium oxide.

In some embodiments, a PN junction is formed between the second doped conductive layer 106 and the substrate 100. The intrinsic passivation layer 105 is inserted between PN junctions to serve as a buffer layer, and the intrinsic passivation layer 105 has good passivation effect on the surface of the substrate 100, so that recombination of carriers can be avoided greatly, and higher minority carrier lifetime and open-circuit voltage are realized.

In some embodiments, the second surface 22 has a textured structure, and the intrinsic passivation layer 105, the second doped conductive layer 106, and the transparent conductive layer 107 are conformal to the textured structure. The light utilization rate of the second surface 22 is increased by the suede structure, so that the quantity of light received by the substrate 100 is increased, and the photoelectric conversion efficiency of the solar cell is improved.

In some embodiments, the substrate 100 has a third doping element, and the conductivity type of the first doping element is the same as the conductivity type of the third doping element. A passivation contact structure and a high-low junction are formed between the substrate 100 and the first doped conductive layer 122, so that carriers in the substrate 100 are promoted to migrate to the first doped conductive layer 122 under the action of the built-in electric field, and are absorbed by the electrode, which is beneficial to improving the battery efficiency of the battery.

In some embodiments, the conductivity type of the second doping element is the same as the conductivity type of the third doping element. The passivation contact structure and the high-low junction are formed between the substrate 100 and the second doped conductive layer 106, so that carriers in the substrate 100 are promoted to migrate to the second doped conductive layer 106 under the action of the built-in electric field and are absorbed by the electrode, and the improvement of the battery efficiency of the battery is facilitated.

In some embodiments, further comprising: a passivation layer 104, wherein the passivation layer 104 is located on the first surface of the substrate of the non-electrode region 11 and the surface of the first doped conductive layer 122; a first electrode 109, the first electrode 109 being located in the electrode region 10, the first electrode 109 being in electrical contact with the first doped conductive layer 122; and a second electrode 108, the second electrode 108 being located in the electrode region 10, the second electrode 109 being in electrical contact with the transparent conductive layer 107.

In some embodiments, the passivation layer 104 may have a single-layer structure or a stacked-layer structure, and the material of the passivation layer 104 may be one or more of silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbonitride, titanium oxide, hafnium oxide, or aluminum oxide.

In some embodiments, the first electrode 109 may be sintered from a burn-through paste. The method of forming the first electrode 109 includes: a screen printing process is used to print a metal paste on the surface of a portion of the passivation layer 104 or the anti-reflection layer. The metal paste may include at least one of silver, rate, copper, tin, gold, lead, or nickel. The metal paste is subjected to a sintering process, in some embodiments, the metal paste has a material of high corrosive composition such as glass therein, such that during the sintering process, the corrosive composition will corrode the passivation layer 104 or the anti-reflection layer, thereby allowing the metal paste to penetrate the passivation layer 104 or the anti-reflection layer to make electrical contact with the first doped conductive layer 122.

In some embodiments, the second electrode 108 may be sintered from a burn-through paste. The method of forming the second electrode 108 includes: a metal paste is printed on a portion of the surface of the first passivation layer 110 or the anti-reflection layer using a screen printing process. The metal paste may include at least one of silver, rate, copper, tin, gold, lead, or nickel. The metal paste is subjected to a sintering process, and in some embodiments, the metal paste has a material of high corrosive composition such as glass therein, so that the corrosive composition will corrode the first passivation layer 110 or the anti-reflection layer during the sintering process, thereby allowing the metal paste to penetrate in the first passivation layer 110 or the anti-reflection layer to be in electrical contact with the substrate 100.

The passivation layer on the surface of the first doped conductive layer may have a morphology as shown in fig. 4, which may not conform to the third surface structure, but may conform to the third surface structure. The contact between the first electrode 109 and the first doped conductive layer may be a partial contact or a complete contact, for example, the first electrode may be in contact with a portion of the top of the third surface structure as shown in fig. 4, or the first electrode may be in contact with the complete microprotrusion structure, or the first electrode may be in contact with not only the microprotrusion structure but also a portion of the first doped conductive layer at the bottom of the microprotrusion structure.

In some embodiments, the second surface has a textured structure, and the intrinsic passivation layer, the second doped conductive layer, and the transparent conductive layer are conformal to the textured structure.

For the solar cell shown in fig. 2 or fig. 4, one of the N-type doping element and the P-type doping element is disposed in the substrate 100, and the first doped conductive layer 122 has the other of the N-type doping element and the P-type doping element, so that a PN junction is formed between the substrate 100 and the first doped conductive layer 122, a new hole-electron pair is formed by solar irradiation on the PN junction, under the action of an electric field built in the P-N junction, a photo-generated hole flows to the P region, a photo-generated electron flows to the N region, and a current is generated after the circuit is completed. For example, when the substrate 100 is N-doped, the substrate 100 is an N-region, the first doped conductive layer 122 is P-doped, the first doped conductive layer 122 is a P-region, the P-type semiconductor has a hole (the P-type semiconductor has one less negative electron and can be regarded as one more positive charge), and the N-type semiconductor has one more free electron to generate electricity, so when the solar light irradiates, the light can excite the electron in the silicon atom (photoelectric effect) to generate convection of the electron and the hole, the electron and the hole are respectively influenced by the built-in potential and are gathered in the two sections of the N-region and the P-region, and at the moment, the outside is connected through the electrode to form a loop, thereby generating current.

For the solar cell shown in fig. 2 or fig. 4, a PN junction is formed between the substrate 100 and the second doped conductive layer 106.

In some embodiments, referring to fig. 6 and 7, fig. 6 is a schematic view of a third cross-sectional structure of fig. 1 along A1-A2; fig. 7 is a schematic view of a third cross-sectional structure of the solar cell of fig. 1 along the section B1-B2, and further includes: an emitter 113, the emitter 113 being located in the electrode region 10 and the non-electrode region 11, the emitter 113 being located between the substrate 100 and the tunneling dielectric layer 121 and between the substrate 100 and the passivation layer 104; the emitter 113 is conformal to the first surface structure 31 and the second surface structure 32.

In some embodiments, a PN junction is formed between the emitter 113 and the substrate 100, and the conductivity type of the first doping element of the first doped conductive layer 122 is the same as the conductivity type of the fifth doping element of the emitter 113.

In some embodiments, referring to fig. 8, fig. 8 is a schematic view of a fourth cross-sectional structure of the cross-section A1-A2 of fig. 1, and the solar cell further includes: and a doped layer 114, wherein the doped layer 114 is located between the surface of the substrate 100 of the non-electrode region 11 and the passivation layer 104, and the conductivity type of the fourth doped element of the doped layer 114 is the same as the conductivity type of the first doped element of the first doped conductive layer 122.

In some embodiments, the doped layer and the first doped conductive layer 122 may be used together as a whole to form a PN junction with the substrate 100, and the doped layer and the first doped conductive layer 122 may also be used as a part of a passivation contact structure, so as to improve the carrier transmission efficiency by forming a high-low junction with the substrate 100.

In some embodiments, the material of doped layer 114 includes at least one of microcrystalline silicon, amorphous silicon, polysilicon, or silicon carbide.

In some embodiments, if the fourth doping concentration of the fourth doping element is less than or equal to the first doping concentration of the first doping element, the doping concentration of the doped layer 114 corresponding to the non-electrode region 11 is lower, the recombination effect is relatively smaller, the doping concentration of the first doped conductive layer 122 corresponding to the electrode region 10 is higher, the contact resistance between the first electrode 109 and the first doped conductive layer 122 is smaller, and more doping elements can also be used as carriers, so as to improve the transmission efficiency of the battery.

It is understood that the first doped conductive layer 122 and the doped layer 114 may be in partial contact or complete contact from side to side, or from top to bottom.

Fig. 9 is a schematic cross-sectional structure of a photovoltaic module according to an embodiment of the application.

Accordingly, according to some embodiments of the present application, a further aspect of the embodiments of the present application provides a photovoltaic module, referring to fig. 9, the photovoltaic module includes: a cell string formed by connecting a plurality of solar cells 40 according to any one of the above embodiments; a packaging adhesive film 41 for covering the surface of the battery string; and a cover plate 42 for covering the surface of the packaging adhesive film 41 facing away from the battery strings.

Specifically, in some embodiments, multiple battery strings may be electrically connected by conductive tape 402. Fig. 9 only illustrates a positional relationship between solar cells, that is, the arrangement directions of electrodes having the same polarity for the cell sheets are the same or the electrodes having positive polarity for each cell sheet are arranged toward the same side, so that the conductive strips are respectively connected to different sides of two adjacent cell sheets. In some embodiments, the battery plates may also be arranged in order of the electrodes with different polarities facing the same side, that is, the electrodes of the adjacent battery plates are respectively arranged in the order of the first polarity, the second polarity, and the first polarity, so that the conductive strip connects two adjacent battery plates on the same side.

In some embodiments, no space is provided between the battery cells, i.e., the battery cells overlap each other.

In some embodiments, the encapsulation film 41 includes a first encapsulation layer covering one of the front side or the back side of the solar cell 40 and a second encapsulation layer covering the other of the front side or the back side of the solar cell 40, and specifically, at least one of the first encapsulation layer or the second encapsulation layer may be an organic encapsulation film such as a polyvinyl butyral (Polyvinyl Butyral, abbreviated as PVB) film, an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene co-elastomer (POE) film, or a polyethylene terephthalate (PET) film.

It will be appreciated that the first and second encapsulant layers also have demarcations before lamination, and that the formation of the photovoltaic module after lamination does not have the concept of the first and second encapsulant layers anymore, i.e. the first and second encapsulant layers already form an integral encapsulant film 41.

In some embodiments, the cover 42 may be a glass cover, a plastic cover, or the like having a light-transmitting function. Specifically, the surface of the cover plate 42 facing the encapsulation film 41 may be a concave-convex surface, thereby increasing the utilization rate of incident light. The cover 42 includes a first cover plate opposite the first encapsulation layer and a second cover plate opposite the second encapsulation layer.

While the application has been described in terms of the preferred embodiment, it is not intended to limit the scope of the claims, and any person skilled in the art can make many variations and modifications without departing from the spirit of the application, so that the scope of the application shall be defined by the claims. Furthermore, the embodiments of the present application described in the specification and the illustrated figures are illustrative only and are not intended to be limiting as to the full scope of the application as claimed.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples of carrying out the utility model and that various changes in form and details may be made therein without departing from the spirit and scope of the utility model. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the utility model, and the scope of the utility model should be assessed accordingly to that of the appended claims.

Claims

1. A solar cell, comprising:

A substrate having a first surface and a second surface, the substrate having alternately arranged electrode regions and non-electrode regions; the first surface of the electrode region is provided with a first surface structure, the first surface of the non-electrode region is provided with a second surface structure, and the roughness of the first surface structure is smaller than that of the second surface structure;

A tunneling dielectric layer covering the first surface structure;

The first doped conductive layer is positioned on one side of the tunneling dielectric layer away from the substrate;

an intrinsic passivation layer on the second surface of the substrate;

A second doped conductive layer located on a side of the intrinsic passivation layer remote from the substrate; the first doped conductive layer has a first doping element, the second doped conductive layer has a second doping element, and the conductivity type of the first doping element is different from the conductivity type of the second doping element;

And the transparent conductive layer covers the surface of the second doped conductive layer.

2. The solar cell of claim 1, wherein the second surface structure comprises a plurality of first raised structures; the first doped conductive layer is provided with a third surface structure on one side far away from the tunneling dielectric layer, the third surface structure comprises a plurality of microprotrusion structures, and the size of each microprotrusion structure is smaller than that of the first protruding structure.

3. The solar cell of claim 2, wherein the microprotrusion structure has a dimension of less than 1um.

4. The solar cell of claim 2, wherein the shape of the microprotrusion structure includes a pyramid shape, a sinusoidal shape, or a parabolic shape.

5. The solar cell of claim 1, wherein the first surface structure comprises a planar face.

6. The solar cell of claim 1 or 5, wherein the tunneling dielectric layer and the first doped conductive layer are conformal with the first surface structure.

7. The solar cell according to claim 1, wherein a third doping element is provided in the substrate, and the first doping element has a conductivity type identical to that of the third doping element or the second doping element has a conductivity type identical to that of the third doping element.

8. The solar cell of claim 1, further comprising: and the emitter is positioned on the first surface of the substrate, the tunneling dielectric layer is positioned on the emitter surface of the electrode area, and the emitter is conformal with the first surface structure and the second surface structure.

9. The solar cell of claim 1 or 2, wherein the second surface has a textured structure, the intrinsic passivation layer, the second doped conductive layer, and the transparent conductive layer being conformal to the textured structure.

10. The solar cell of claim 1, further comprising: a first electrode located in the electrode region, the first electrode in electrical contact with the first doped conductive layer; and the second electrode is positioned in the electrode area and is electrically contacted with the transparent conductive layer.

11. A photovoltaic module, comprising:

A cell string formed by connecting a plurality of solar cells according to any one of claims 1 to 10;

The packaging adhesive film is used for covering the surface of the battery string;

and the cover plate is used for covering the surface of the packaging adhesive film, which is away from the battery strings.